NEWS
author kleing
Mon Mar 01 05:21:43 2004 +0100 (2004-03-01)
changeset 14418 b62323c85134
parent 14401 477380c74c1d
child 14427 cea7d2f76112
permissions -rw-r--r--
union/intersection over intervals
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
    10   Replaces linorder.ML.
    11 
    12 * Pure: Greek letters (except small lambda, \<lambda>), as well as gothic
    13   (\<aa>...\<zz>\<AA>...\<ZZ>), caligraphic (\<A>...\<Z>), and euler
    14   (\<a>...\<z>), are now considered normal letters, and can therefore
    15   be used anywhere where an ASCII letter (a...zA...Z) has until
    16   now. COMPATIBILITY: This obviously changes the parsing of some
    17   terms, especially where a symbol has been used as a binder, say
    18   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    19   as an identifier.  Fix it by inserting a space around former
    20   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    21   existing theory and ML files.
    22 
    23 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
    24 
    25 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now 
    26   allowed in identifiers. Similar to greek letters \<^isub> is now considered 
    27   a normal (but invisible) letter. For multiple letter subscripts repeat 
    28   \<^isub> like this: x\<^isub>1\<^isub>2. 
    29 
    30 * Pure: There are now sub-/superscripts that can span more than one
    31   character. Text between \<^bsub> and \<^esub> is set in subscript in
    32   PG and LaTeX, text between \<^bsup> and \<^esup> in superscript. The
    33   new control characters are not identifier parts.
    34 
    35 * Pure: Control-symbols of the form \<^raw...> will literally print the
    36   content of ... to the latex file instead of \isacntrl... . The ... 
    37   accepts all printable characters excluding the end bracket >.
    38 
    39 * Pure: Symbols may only start with one backslash: \<...>. \\<...> is no 
    40   longer accepted by the scanner.
    41 
    42 * Pure: Using new Isar command "finalconsts" (or the ML functions
    43   Theory.add_finals or Theory.add_finals_i) it is now possible to
    44   declare constants "final", which prevents their being given a definition
    45   later.  It is useful for constants whose behaviour is fixed axiomatically
    46   rather than definitionally, such as the meta-logic connectives.
    47 
    48 *** Isar ***
    49 
    50 * Tactic emulation methods ?rule_tac, cut_tac, subgoal_tac and thin_tac:
    51   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    52     locales are no longer forced to write Isar proof scripts.
    53     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    54     emulations.
    55   - INCOMPATIBILITY: names of variables to be instantiated may no
    56     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    57     This is consistent with the instantiation attribute "where".
    58 
    59 * Attributes "where" and "of":
    60   - Now take type variables of instantiated theorem into account when reading
    61     the instantiation string.  This fixes a bug that caused instantiated
    62     theorems to have too special types in some circumstances.
    63   - "where" permits explicit instantiations of type variables.
    64 
    65 * Calculation commands "moreover" and "also":
    66   Do not reset facts ("this") any more.
    67 
    68 * Locales:
    69   - Goal statements involving the context element "includes" no longer
    70     generate theorems with internal delta predicates (those ending on
    71     "_axioms") in the premise.
    72     Resolve particular premise with <locale>.intro to obtain old form.
    73   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    74     specification and "includes" elements in goal statement.
    75   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
    76     [intro?] and [elim?] (respectively) by default.
    77 
    78 * HOL: Tactic emulation methods induct_tac and case_tac understand static
    79   (Isar) contexts.
    80 
    81 *** HOL ***
    82 
    83 * Simplifier:
    84   - Much improved handling of linear and partial orders.
    85     Reasoners for linear and partial orders are set up for type classes
    86     "linorder" and "order" respectively, and are added to the default simpset
    87     as solvers.  This means that the simplifier can build transitivity chains
    88     to solve goals from the assumptions.
    89   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
    90     of blast or auto after simplification become unnecessary because the goal
    91     is solved by simplification already.
    92 
    93 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws, 
    94     all proved in axiomatic type classes for semirings, rings and fields.
    95 
    96 * Numerics:
    97   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
    98     now formalized using the Ring_and_Field theory mentioned above. 
    99   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   100     than before, because now they are set up once in a generic manner.
   101   - INCOMPATIBILITY: many type-specific instances of laws proved in 
   102     Ring_and_Field are no longer available.
   103 
   104 * Type "rat" of the rational numbers is now available in HOL-Complex.
   105 
   106 * Records:
   107   - Record types are now by default printed with their type abbreviation
   108     instead of the list of all field types. This can be configured via
   109     the reference "print_record_type_abbr".
   110   - Simproc "record_upd_simproc" for simplification of multiple updates added 
   111     (not enabled by default).
   112   - Tactic "record_split_simp_tac" to split and simplify records added.
   113  
   114 * 'specification' command added, allowing for definition by
   115   specification.  There is also an 'ax_specification' command that
   116   introduces the new constants axiomatically.
   117 
   118 * arith(_tac) is now able to generate counterexamples for reals as well.
   119 
   120 * HOL-Algebra: new locale "ring" for non-commutative rings.
   121 
   122 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   123  defintions, thanks to Sava Krsti\'{c} and John Matthews.
   124 
   125 * Unions and Intersections:
   126   The x-symbol output syntax of UN and INT has been changed
   127   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   128   i.e. the index formulae has become a subscript, like in normal math.
   129   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   130   The subscript version is also accepted as input syntax.
   131 
   132 * Unions and Intersections over Intervals:
   133   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is 
   134   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A" 
   135   like in normal math, and corresponding versions for < and for intersection.
   136 
   137 * ML: the legacy theory structures Int and List have been removed. They had
   138   conflicted with ML Basis Library structures having the same names.
   139 
   140 New in Isabelle2003 (May 2003)
   141 --------------------------------
   142 
   143 *** General ***
   144 
   145 * Provers/simplifier:
   146 
   147   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   148     Assumptions are now subject to complete mutual simplification,
   149     not just from left to right. The simplifier now preserves
   150     the order of assumptions.
   151 
   152     Potential INCOMPATIBILITY:
   153 
   154     -- simp sometimes diverges where the old version did
   155        not, e.g. invoking simp on the goal
   156 
   157         [| P (f x); y = x; f x = f y |] ==> Q
   158 
   159        now gives rise to the infinite reduction sequence
   160 
   161         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   162 
   163        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   164        kind of problem.
   165 
   166     -- Tactics combining classical reasoner and simplification (such as auto)
   167        are also affected by this change, because many of them rely on
   168        simp. They may sometimes diverge as well or yield a different numbers
   169        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   170        in case of problems. Sometimes subsequent calls to the classical
   171        reasoner will fail because a preceeding call to the simplifier too
   172        eagerly simplified the goal, e.g. deleted redundant premises.
   173 
   174   - The simplifier trace now shows the names of the applied rewrite rules
   175 
   176   - You can limit the number of recursive invocations of the simplifier
   177     during conditional rewriting (where the simplifie tries to solve the
   178     conditions before applying the rewrite rule):
   179     ML "simp_depth_limit := n"
   180     where n is an integer. Thus you can force termination where previously
   181     the simplifier would diverge.
   182 
   183   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   184 
   185   - No longer aborts on failed congruence proof.  Instead, the
   186     congruence is ignored.
   187 
   188 * Pure: New generic framework for extracting programs from constructive
   189   proofs. See HOL/Extraction.thy for an example instantiation, as well
   190   as HOL/Extraction for some case studies.
   191 
   192 * Pure: The main goal of the proof state is no longer shown by default, only
   193 the subgoals. This behaviour is controlled by a new flag.
   194    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   195 (ML: Proof.show_main_goal).
   196 
   197 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   198 rules whose conclusion matches subgoal 1:
   199       PG menu: Isabelle/Isar -> Show me -> matching rules
   200 The rules are ordered by how closely they match the subgoal.
   201 In particular, rules that solve a subgoal outright are displayed first
   202 (or rather last, the way they are printed).
   203 (ML: ProofGeneral.print_intros())
   204 
   205 * Pure: New flag trace_unify_fail causes unification to print
   206 diagnostic information (PG: in trace buffer) when it fails. This is
   207 useful for figuring out why single step proofs like rule, erule or
   208 assumption failed.
   209 
   210 * Pure: Locale specifications now produce predicate definitions
   211 according to the body of text (covering assumptions modulo local
   212 definitions); predicate "loc_axioms" covers newly introduced text,
   213 while "loc" is cumulative wrt. all included locale expressions; the
   214 latter view is presented only on export into the global theory
   215 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   216 on the old view without predicates;
   217 
   218 * Pure: predefined locales "var" and "struct" are useful for sharing
   219 parameters (as in CASL, for example); just specify something like
   220 ``var x + var y + struct M'' as import;
   221 
   222 * Pure: improved thms_containing: proper indexing of facts instead of
   223 raw theorems; check validity of results wrt. current name space;
   224 include local facts of proof configuration (also covers active
   225 locales), cover fixed variables in index; may use "_" in term
   226 specification; an optional limit for the number of printed facts may
   227 be given (the default is 40);
   228 
   229 * Pure: disallow duplicate fact bindings within new-style theory files
   230 (batch-mode only);
   231 
   232 * Provers: improved induct method: assumptions introduced by case
   233 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   234 the goal statement); "foo" still refers to all facts collectively;
   235 
   236 * Provers: the function blast.overloaded has been removed: all constants
   237 are regarded as potentially overloaded, which improves robustness in exchange
   238 for slight decrease in efficiency;
   239 
   240 * Provers/linorder: New generic prover for transitivity reasoning over
   241 linear orders.  Note: this prover is not efficient!
   242 
   243 * Isar: preview of problems to finish 'show' now produce an error
   244 rather than just a warning (in interactive mode);
   245 
   246 
   247 *** HOL ***
   248 
   249 * arith(_tac)
   250 
   251  - Produces a counter example if it cannot prove a goal.
   252    Note that the counter example may be spurious if the goal is not a formula
   253    of quantifier-free linear arithmetic.
   254    In ProofGeneral the counter example appears in the trace buffer.
   255 
   256  - Knows about div k and mod k where k is a numeral of type nat or int.
   257 
   258  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   259    linear arithmetic fails. This takes account of quantifiers and divisibility.
   260    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   261 
   262 * simp's arithmetic capabilities have been enhanced a bit: it now
   263 takes ~= in premises into account (by performing a case split);
   264 
   265 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   266 are distributed over a sum of terms;
   267 
   268 * New tactic "trans_tac" and method "trans" instantiate
   269 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   270 "<=", "<" and "="). 
   271 
   272 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   273 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   274 
   275 * 'typedef' command has new option "open" to suppress the set
   276 definition;
   277 
   278 * functions Min and Max on finite sets have been introduced (theory
   279 Finite_Set);
   280 
   281 * attribute [symmetric] now works for relations as well; it turns
   282 (x,y) : R^-1 into (y,x) : R, and vice versa;
   283 
   284 * induct over a !!-quantified statement (say !!x1..xn):
   285   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   286 
   287 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   288 %x. None. Warning: empty_def now refers to the previously hidden definition
   289 of the empty set.
   290 
   291 * Algebra: formalization of classical algebra.  Intended as base for
   292 any algebraic development in Isabelle.  Currently covers group theory
   293 (up to Sylow's theorem) and ring theory (Universal Property of
   294 Univariate Polynomials).  Contributions welcome;
   295 
   296 * GroupTheory: deleted, since its material has been moved to Algebra;
   297 
   298 * Complex: new directory of the complex numbers with numeric constants, 
   299 nonstandard complex numbers, and some complex analysis, standard and 
   300 nonstandard (Jacques Fleuriot);
   301 
   302 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   303 
   304 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   305 Fleuriot);
   306 
   307 * Real/HahnBanach: updated and adapted to locales;
   308 
   309 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   310 Gray and Kramer);
   311 
   312 * UNITY: added the Meier-Sanders theory of progress sets;
   313 
   314 * MicroJava: bytecode verifier and lightweight bytecode verifier
   315 as abstract algorithms, instantiated to the JVM;
   316 
   317 * Bali: Java source language formalization. Type system, operational
   318 semantics, axiomatic semantics. Supported language features:
   319 classes, interfaces, objects,virtual methods, static methods,
   320 static/instance fields, arrays, access modifiers, definite
   321 assignment, exceptions.
   322 
   323 
   324 *** ZF ***
   325 
   326 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   327 universe, etc.);
   328 
   329 * Main ZF: virtually all theories converted to new-style format;
   330 
   331 
   332 *** ML ***
   333 
   334 * Pure: Tactic.prove provides sane interface for internal proofs;
   335 omits the infamous "standard" operation, so this is more appropriate
   336 than prove_goalw_cterm in many situations (e.g. in simprocs);
   337 
   338 * Pure: improved error reporting of simprocs;
   339 
   340 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   341 up simprocs;
   342 
   343 
   344 *** Document preparation ***
   345 
   346 * uses \par instead of \\ for line breaks in theory text. This may
   347 shift some page breaks in large documents. To get the old behaviour
   348 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   349 
   350 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   351 other packages
   352 
   353 * \<euro> now needs package babel/greek instead of marvosym (which
   354 broke \Rightarrow)
   355 
   356 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   357 textcomp package)
   358 
   359 
   360 New in Isabelle2002 (March 2002)
   361 --------------------------------
   362 
   363 *** Document preparation ***
   364 
   365 * greatly simplified document preparation setup, including more
   366 graceful interpretation of isatool usedir -i/-d/-D options, and more
   367 instructive isatool mkdir; users should basically be able to get
   368 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   369 users may run a separate document processing stage manually like this:
   370 "isatool usedir -D output HOL Test && isatool document Test/output";
   371 
   372 * theory dependency graph may now be incorporated into documents;
   373 isatool usedir -g true will produce session_graph.eps/.pdf for use
   374 with \includegraphics of LaTeX;
   375 
   376 * proper spacing of consecutive markup elements, especially text
   377 blocks after section headings;
   378 
   379 * support bold style (for single symbols only), input syntax is like
   380 this: "\<^bold>\<alpha>" or "\<^bold>A";
   381 
   382 * \<bullet> is now output as bold \cdot by default, which looks much
   383 better in printed text;
   384 
   385 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   386 note that these symbols are currently unavailable in Proof General /
   387 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   388 
   389 * isatool latex no longer depends on changed TEXINPUTS, instead
   390 isatool document copies the Isabelle style files to the target
   391 location;
   392 
   393 
   394 *** Isar ***
   395 
   396 * Pure/Provers: improved proof by cases and induction;
   397   - 'case' command admits impromptu naming of parameters (such as
   398     "case (Suc n)");
   399   - 'induct' method divinates rule instantiation from the inductive
   400     claim; no longer requires excessive ?P bindings for proper
   401     instantiation of cases;
   402   - 'induct' method properly enumerates all possibilities of set/type
   403     rules; as a consequence facts may be also passed through *type*
   404     rules without further ado;
   405   - 'induct' method now derives symbolic cases from the *rulified*
   406     rule (before it used to rulify cases stemming from the internal
   407     atomized version); this means that the context of a non-atomic
   408     statement becomes is included in the hypothesis, avoiding the
   409     slightly cumbersome show "PROP ?case" form;
   410   - 'induct' may now use elim-style induction rules without chaining
   411     facts, using ``missing'' premises from the goal state; this allows
   412     rules stemming from inductive sets to be applied in unstructured
   413     scripts, while still benefitting from proper handling of non-atomic
   414     statements; NB: major inductive premises need to be put first, all
   415     the rest of the goal is passed through the induction;
   416   - 'induct' proper support for mutual induction involving non-atomic
   417     rule statements (uses the new concept of simultaneous goals, see
   418     below);
   419   - append all possible rule selections, but only use the first
   420     success (no backtracking);
   421   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   422   - undeclared rule case names default to numbers 1, 2, 3, ...;
   423   - added 'print_induct_rules' (covered by help item in recent Proof
   424     General versions);
   425   - moved induct/cases attributes to Pure, methods to Provers;
   426   - generic method setup instantiated for FOL and HOL;
   427 
   428 * Pure: support multiple simultaneous goal statements, for example
   429 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   430 meta-level mechanism, this acts as if several individual goals had
   431 been stated separately; in particular common proof methods need to be
   432 repeated in order to cover all claims; note that a single elimination
   433 step is *not* sufficient to establish the two conjunctions, so this
   434 fails:
   435 
   436   assume "A & B" then have A and B ..   (*".." fails*)
   437 
   438 better use "obtain" in situations as above; alternative refer to
   439 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   440 
   441 * Pure: proper integration with ``locales''; unlike the original
   442 version by Florian Kammüller, Isar locales package high-level proof
   443 contexts rather than raw logical ones (e.g. we admit to include
   444 attributes everywhere); operations on locales include merge and
   445 rename; support for implicit arguments (``structures''); simultaneous
   446 type-inference over imports and text; see also HOL/ex/Locales.thy for
   447 some examples;
   448 
   449 * Pure: the following commands have been ``localized'', supporting a
   450 target locale specification "(in name)": 'lemma', 'theorem',
   451 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   452 stored both within the locale and at the theory level (exported and
   453 qualified by the locale name);
   454 
   455 * Pure: theory goals may now be specified in ``long'' form, with
   456 ad-hoc contexts consisting of arbitrary locale elements. for example
   457 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   458 definitions may be given, too); the result is a meta-level rule with
   459 the context elements being discharged in the obvious way;
   460 
   461 * Pure: new proof command 'using' allows to augment currently used
   462 facts after a goal statement ('using' is syntactically analogous to
   463 'apply', but acts on the goal's facts only); this allows chained facts
   464 to be separated into parts given before and after a claim, as in
   465 ``from a and b have C using d and e <proof>'';
   466 
   467 * Pure: renamed "antecedent" case to "rule_context";
   468 
   469 * Pure: new 'judgment' command records explicit information about the
   470 object-logic embedding (used by several tools internally); no longer
   471 use hard-wired "Trueprop";
   472 
   473 * Pure: added 'corollary' command;
   474 
   475 * Pure: fixed 'token_translation' command;
   476 
   477 * Pure: removed obsolete 'exported' attribute;
   478 
   479 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   480 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   481 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   482 
   483 * Pure: method 'atomize' presents local goal premises as object-level
   484 statements (atomic meta-level propositions); setup controlled via
   485 rewrite rules declarations of 'atomize' attribute; example
   486 application: 'induct' method with proper rule statements in improper
   487 proof *scripts*;
   488 
   489 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   490 now consider the syntactic context of assumptions, giving a better
   491 chance to get type-inference of the arguments right (this is
   492 especially important for locales);
   493 
   494 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   495 mode;
   496 
   497 * Pure/obtain: the formal conclusion "thesis", being marked as
   498 ``internal'', may no longer be reference directly in the text;
   499 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   500 situations;
   501 
   502 * Pure: generic 'sym' attribute which declares a rule both as pure
   503 'elim?' and for the 'symmetric' operation;
   504 
   505 * Pure: marginal comments ``--'' may now occur just anywhere in the
   506 text; the fixed correlation with particular command syntax has been
   507 discontinued;
   508 
   509 * Pure: new method 'rules' is particularly well-suited for proof
   510 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   511 but often produces more compact proof terms with less detours;
   512 
   513 * Pure/Provers/classical: simplified integration with pure rule
   514 attributes and methods; the classical "intro?/elim?/dest?"
   515 declarations coincide with the pure ones; the "rule" method no longer
   516 includes classically swapped intros; "intro" and "elim" methods no
   517 longer pick rules from the context; also got rid of ML declarations
   518 AddXIs/AddXEs/AddXDs; all of this has some potential for
   519 INCOMPATIBILITY;
   520 
   521 * Provers/classical: attribute 'swapped' produces classical inversions
   522 of introduction rules;
   523 
   524 * Provers/simplifier: 'simplified' attribute may refer to explicit
   525 rules instead of full simplifier context; 'iff' attribute handles
   526 conditional rules;
   527 
   528 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   529 
   530 * HOL: 'recdef' now fails on unfinished automated proofs, use
   531 "(permissive)" option to recover old behavior;
   532 
   533 * HOL: 'inductive' no longer features separate (collective) attributes
   534 for 'intros' (was found too confusing);
   535 
   536 * HOL: properly declared induction rules less_induct and
   537 wf_induct_rule;
   538 
   539 
   540 *** HOL ***
   541 
   542 * HOL: moved over to sane numeral syntax; the new policy is as
   543 follows:
   544 
   545   - 0 and 1 are polymorphic constants, which are defined on any
   546   numeric type (nat, int, real etc.);
   547 
   548   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   549   binary representation internally;
   550 
   551   - type nat has special constructor Suc, and generally prefers Suc 0
   552   over 1::nat and Suc (Suc 0) over 2::nat;
   553 
   554 This change may cause significant problems of INCOMPATIBILITY; here
   555 are some hints on converting existing sources:
   556 
   557   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   558   entities, so expressions involving "-" (unary or binary minus) need
   559   to be spaced properly;
   560 
   561   - existing occurrences of "1" may need to be constraint "1::nat" or
   562   even replaced by Suc 0; similar for old "2";
   563 
   564   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   565 
   566   - remove all special provisions on numerals in proofs;
   567 
   568 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   569 representation (depends on bin_arith_simps in the default context);
   570 
   571 * HOL: symbolic syntax for x^2 (numeral 2);
   572 
   573 * HOL: the class of all HOL types is now called "type" rather than
   574 "term"; INCOMPATIBILITY, need to adapt references to this type class
   575 in axclass/classes, instance/arities, and (usually rare) occurrences
   576 in typings (of consts etc.); internally the class is called
   577 "HOL.type", ML programs should refer to HOLogic.typeS;
   578 
   579 * HOL/record package improvements:
   580   - new derived operations "fields" to build a partial record section,
   581     "extend" to promote a fixed record to a record scheme, and
   582     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   583     declared as simp by default;
   584   - shared operations ("more", "fields", etc.) now need to be always
   585     qualified) --- potential INCOMPATIBILITY;
   586   - removed "make_scheme" operations (use "make" with "extend") --
   587     INCOMPATIBILITY;
   588   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   589   - provides cases/induct rules for use with corresponding Isar
   590     methods (for concrete records, record schemes, concrete more
   591     parts, and schematic more parts -- in that order);
   592   - internal definitions directly based on a light-weight abstract
   593     theory of product types over typedef rather than datatype;
   594 
   595 * HOL: generic code generator for generating executable ML code from
   596 specifications; specific support for HOL constructs such as inductive
   597 datatypes and sets, as well as recursive functions; can be invoked
   598 via 'generate_code' theory section;
   599 
   600 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   601 
   602 * HOL: consolidated and renamed several theories.  In particular:
   603 	Ord.thy has been absorbed into HOL.thy
   604 	String.thy has been absorbed into List.thy
   605  
   606 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   607 (beware of argument permutation!);
   608 
   609 * HOL: linorder_less_split superseded by linorder_cases;
   610 
   611 * HOL/List: "nodups" renamed to "distinct";
   612 
   613 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   614 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   615   - Ex_def has changed, now need to use some_eq_ex
   616 
   617 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   618 in this (rare) case use:
   619 
   620   delSWrapper "split_all_tac"
   621   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   622 
   623 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   624 MAY FAIL;
   625 
   626 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   627 Isabelle's type classes, ^ on functions and relations has too general
   628 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   629 necessary to attach explicit type constraints;
   630 
   631 * HOL/Relation: the prefix name of the infix "O" has been changed from
   632 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   633 renamed accordingly (eg "compI" -> "rel_compI").
   634 
   635 * HOL: syntax translations now work properly with numerals and records
   636 expressions;
   637 
   638 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   639 of "lam" -- INCOMPATIBILITY;
   640 
   641 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   642 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   643 renamed "Product_Type.unit";
   644 
   645 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   646 
   647 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   648 the "cases" method);
   649 
   650 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   651 Florian Kammüller);
   652 
   653 * HOL/IMP: updated and converted to new-style theory format; several
   654 parts turned into readable document, with proper Isar proof texts and
   655 some explanations (by Gerwin Klein);
   656 
   657 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   658 
   659 * HOL-Hyperreal is now a logic image;
   660 
   661 
   662 *** HOLCF ***
   663 
   664 * Isar: consts/constdefs supports mixfix syntax for continuous
   665 operations;
   666 
   667 * Isar: domain package adapted to new-style theory format, e.g. see
   668 HOLCF/ex/Dnat.thy;
   669 
   670 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   671 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   672 lift.induct_tac, always use UU instead of Undef;
   673 
   674 * HOLCF/IMP: updated and converted to new-style theory;
   675 
   676 
   677 *** ZF ***
   678 
   679 * Isar: proper integration of logic-specific tools and packages,
   680 including theory commands '(co)inductive', '(co)datatype',
   681 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   682 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   683 
   684 * theory Main no longer includes AC; for the Axiom of Choice, base
   685 your theory on Main_ZFC;
   686 
   687 * the integer library now covers quotients and remainders, with many
   688 laws relating division to addition, multiplication, etc.;
   689 
   690 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   691 typeless version of the formalism;
   692 
   693 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   694 format;
   695 
   696 * ZF/Induct: new directory for examples of inductive definitions,
   697 including theory Multiset for multiset orderings; converted to
   698 new-style theory format;
   699 
   700 * ZF: many new theorems about lists, ordinals, etc.;
   701 
   702 
   703 *** General ***
   704 
   705 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   706 variable proof controls level of detail: 0 = no proofs (only oracle
   707 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   708 also ref manual for further ML interfaces;
   709 
   710 * Pure/axclass: removed obsolete ML interface
   711 goal_subclass/goal_arity;
   712 
   713 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   714 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   715 separate tokens, so expressions involving minus need to be spaced
   716 properly;
   717 
   718 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   719 rather than "infixl" or "infixr";
   720 
   721 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   722 sort constraint specifications in type inference; e.g. "x::_::foo"
   723 ensures that the type of "x" is of sort "foo" (but not necessarily a
   724 type variable);
   725 
   726 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   727 control output of nested => (types); the default behavior is
   728 "type_brackets";
   729 
   730 * Pure/syntax: builtin parse translation for "_constify" turns valued
   731 tokens into AST constants;
   732 
   733 * Pure/syntax: prefer later declarations of translations and print
   734 translation functions; potential INCOMPATIBILITY: need to reverse
   735 multiple declarations for same syntax element constant;
   736 
   737 * Pure/show_hyps reset by default (in accordance to existing Isar
   738 practice);
   739 
   740 * Provers/classical: renamed addaltern to addafter, addSaltern to
   741 addSafter;
   742 
   743 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   744 as well;
   745 
   746 * system: tested support for MacOS X; should be able to get Isabelle +
   747 Proof General to work in a plain Terminal after installing Poly/ML
   748 (e.g. from the Isabelle distribution area) and GNU bash alone
   749 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   750 support requires further installations, e.g. from
   751 http://fink.sourceforge.net/);
   752 
   753 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   754 
   755 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   756 of 40 MB), cf. ML_OPTIONS;
   757 
   758 * system: Proof General keywords specification is now part of the
   759 Isabelle distribution (see etc/isar-keywords.el);
   760 
   761 * system: support for persistent Proof General sessions (refrain from
   762 outdating all loaded theories on startup); user may create writable
   763 logic images like this: ``isabelle -q HOL Test'';
   764 
   765 * system: smart selection of Isabelle process versus Isabelle
   766 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   767 run both "isabelle" and "Isabelle" even if file names are badly
   768 damaged (executable inspects the case of the first letter of its own
   769 name); added separate "isabelle-process" and "isabelle-interface";
   770 
   771 * system: refrain from any attempt at filtering input streams; no
   772 longer support ``8bit'' encoding of old isabelle font, instead proper
   773 iso-latin characters may now be used; the related isatools
   774 "symbolinput" and "nonascii" have disappeared as well;
   775 
   776 * system: removed old "xterm" interface (the print modes "xterm" and
   777 "xterm_color" are still available for direct use in a suitable
   778 terminal);
   779 
   780 
   781 
   782 New in Isabelle99-2 (February 2001)
   783 -----------------------------------
   784 
   785 *** Overview of INCOMPATIBILITIES ***
   786 
   787 * HOL: please note that theories in the Library and elsewhere often use the
   788 new-style (Isar) format; to refer to their theorems in an ML script you must
   789 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   790 
   791 * HOL: inductive package no longer splits induction rule aggressively,
   792 but only as far as specified by the introductions given; the old
   793 format may be recovered via ML function complete_split_rule or attribute
   794 'split_rule (complete)';
   795 
   796 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   797 gfp_Tarski to gfp_unfold;
   798 
   799 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   800 
   801 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   802 relation); infix "^^" has been renamed "``"; infix "``" has been
   803 renamed "`"; "univalent" has been renamed "single_valued";
   804 
   805 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   806 operation;
   807 
   808 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   809 
   810 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   811 
   812 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   813 consequence, it is no longer monotonic wrt. the local goal context
   814 (which is now passed through the inductive cases);
   815 
   816 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   817 \<gg> to \<ggreater>;
   818 
   819 
   820 *** Document preparation ***
   821 
   822 * \isabellestyle{NAME} selects version of Isabelle output (currently
   823 available: are "it" for near math-mode best-style output, "sl" for
   824 slanted text style, and "tt" for plain type-writer; if no
   825 \isabellestyle command is given, output is according to slanted
   826 type-writer);
   827 
   828 * support sub/super scripts (for single symbols only), input syntax is
   829 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   830 
   831 * some more standard symbols; see Appendix A of the system manual for
   832 the complete list of symbols defined in isabellesym.sty;
   833 
   834 * improved isabelle style files; more abstract symbol implementation
   835 (should now use \isamath{...} and \isatext{...} in custom symbol
   836 definitions);
   837 
   838 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   839 state; Note that presentation of goal states does not conform to
   840 actual human-readable proof documents.  Please do not include goal
   841 states into document output unless you really know what you are doing!
   842 
   843 * proper indentation of antiquoted output with proportional LaTeX
   844 fonts;
   845 
   846 * no_document ML operator temporarily disables LaTeX document
   847 generation;
   848 
   849 * isatool unsymbolize tunes sources for plain ASCII communication;
   850 
   851 
   852 *** Isar ***
   853 
   854 * Pure: Isar now suffers initial goal statements to contain unbound
   855 schematic variables (this does not conform to actual readable proof
   856 documents, due to unpredictable outcome and non-compositional proof
   857 checking); users who know what they are doing may use schematic goals
   858 for Prolog-style synthesis of proven results;
   859 
   860 * Pure: assumption method (an implicit finishing) now handles actual
   861 rules as well;
   862 
   863 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   864 initial goal, declare "that" only as Pure intro (only for single
   865 steps); the "that" rule assumption may now be involved in implicit
   866 finishing, thus ".." becomes a feasible for trivial obtains;
   867 
   868 * Pure: default proof step now includes 'intro_classes'; thus trivial
   869 instance proofs may be performed by "..";
   870 
   871 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   872 statements as well;
   873 
   874 * Pure: more robust selection of calculational rules;
   875 
   876 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   877 rule (as well as the assumption rule);
   878 
   879 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   880 lemmas, using the graph browser tool;
   881 
   882 * Pure: predict failure of "show" in interactive mode;
   883 
   884 * Pure: 'thms_containing' now takes actual terms as arguments;
   885 
   886 * HOL: improved method 'induct' --- now handles non-atomic goals
   887 (potential INCOMPATIBILITY); tuned error handling;
   888 
   889 * HOL: cases and induct rules now provide explicit hints about the
   890 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   891 any remaining facts are inserted into the goal verbatim;
   892 
   893 * HOL: local contexts (aka cases) may now contain term bindings as
   894 well; the 'cases' and 'induct' methods new provide a ?case binding for
   895 the result to be shown in each case;
   896 
   897 * HOL: added 'recdef_tc' command;
   898 
   899 * isatool convert assists in eliminating legacy ML scripts;
   900 
   901 
   902 *** HOL ***
   903 
   904 * HOL/Library: a collection of generic theories to be used together
   905 with main HOL; the theory loader path already includes this directory
   906 by default; the following existing theories have been moved here:
   907 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   908 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   909 
   910 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   911 modelling and verification task performed in Isabelle/HOL +
   912 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   913 
   914 * HOL/Algebra: special summation operator SUM no longer exists, it has
   915 been replaced by setsum; infix 'assoc' now has priority 50 (like
   916 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   917 'domain', this makes the theory consistent with mathematical
   918 literature;
   919 
   920 * HOL basics: added overloaded operations "inverse" and "divide"
   921 (infix "/"), syntax for generic "abs" operation, generic summation
   922 operator \<Sum>;
   923 
   924 * HOL/typedef: simplified package, provide more useful rules (see also
   925 HOL/subset.thy);
   926 
   927 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   928 now expressed as a proper nested rule (old-style tactic scripts may
   929 require atomize_strip_tac to cope with non-atomic premises);
   930 
   931 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   932 to "split_conv" (old name still available for compatibility);
   933 
   934 * HOL: improved concrete syntax for strings (e.g. allows translation
   935 rules with string literals);
   936 
   937 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   938  and Fleuriot's mechanization of analysis, including the transcendental
   939  functions for the reals;
   940 
   941 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   942 
   943 
   944 *** CTT ***
   945 
   946 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   947 "lam" is displayed as TWO lambda-symbols
   948 
   949 * CTT: theory Main now available, containing everything (that is, Bool
   950 and Arith);
   951 
   952 
   953 *** General ***
   954 
   955 * Pure: the Simplifier has been implemented properly as a derived rule
   956 outside of the actual kernel (at last!); the overall performance
   957 penalty in practical applications is about 50%, while reliability of
   958 the Isabelle inference kernel has been greatly improved;
   959 
   960 * print modes "brackets" and "no_brackets" control output of nested =>
   961 (types) and ==> (props); the default behaviour is "brackets";
   962 
   963 * Provers: fast_tac (and friends) now handle actual object-logic rules
   964 as assumptions as well;
   965 
   966 * system: support Poly/ML 4.0;
   967 
   968 * system: isatool install handles KDE version 1 or 2;
   969 
   970 
   971 
   972 New in Isabelle99-1 (October 2000)
   973 ----------------------------------
   974 
   975 *** Overview of INCOMPATIBILITIES ***
   976 
   977 * HOL: simplification of natural numbers is much changed; to partly
   978 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   979 issue the following ML commands:
   980 
   981   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   982   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   983 
   984 * HOL: simplification no longer dives into case-expressions; this is
   985 controlled by "t.weak_case_cong" for each datatype t;
   986 
   987 * HOL: nat_less_induct renamed to less_induct;
   988 
   989 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   990 fixsome to patch .thy and .ML sources automatically;
   991 
   992   select_equality  -> some_equality
   993   select_eq_Ex     -> some_eq_ex
   994   selectI2EX       -> someI2_ex
   995   selectI2         -> someI2
   996   selectI          -> someI
   997   select1_equality -> some1_equality
   998   Eps_sym_eq       -> some_sym_eq_trivial
   999   Eps_eq           -> some_eq_trivial
  1000 
  1001 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1002 
  1003 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1004 instead);
  1005 
  1006 * HOL: the recursion equations generated by 'recdef' are now called
  1007 f.simps instead of f.rules;
  1008 
  1009 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1010 
  1011 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1012 sometimes be needed;
  1013 
  1014 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1015 
  1016 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1017 
  1018 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1019 product is now "<*>" instead of "Times"; the lexicographic product is
  1020 now "<*lex*>" instead of "**";
  1021 
  1022 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1023 of main HOL, but was unused); better use HOL's datatype package;
  1024 
  1025 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1026 the old syntax may be recovered as follows:
  1027 
  1028   syntax (symbols)
  1029     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1030       (infixl "\\<oplus>" 100)
  1031 
  1032 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1033 
  1034 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1035 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1036 internally;
  1037 
  1038 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1039 changed from A/r to A//r;
  1040 
  1041 * ZF: new treatment of arithmetic (nat & int) may break some old
  1042 proofs;
  1043 
  1044 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1045 rulify -> rule_format, elimify -> elim_format, ...);
  1046 
  1047 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1048 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1049 should have to change intro!! to intro? only); replaced "delrule" by
  1050 "rule del";
  1051 
  1052 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1053 
  1054 * Provers: strengthened force_tac by using new first_best_tac;
  1055 
  1056 * LaTeX document preparation: several changes of isabelle.sty (see
  1057 lib/texinputs);
  1058 
  1059 
  1060 *** Document preparation ***
  1061 
  1062 * formal comments (text blocks etc.) in new-style theories may now
  1063 contain antiquotations of thm/prop/term/typ/text to be presented
  1064 according to latex print mode; concrete syntax is like this:
  1065 @{term[show_types] "f(x) = a + x"};
  1066 
  1067 * isatool mkdir provides easy setup of Isabelle session directories,
  1068 including proper document sources;
  1069 
  1070 * generated LaTeX sources are now deleted after successful run
  1071 (isatool document -c); may retain a copy somewhere else via -D option
  1072 of isatool usedir;
  1073 
  1074 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1075 style files, achieving self-contained LaTeX sources and simplifying
  1076 LaTeX debugging;
  1077 
  1078 * old-style theories now produce (crude) LaTeX output as well;
  1079 
  1080 * browser info session directories are now self-contained (may be put
  1081 on WWW server seperately); improved graphs of nested sessions; removed
  1082 graph for 'all sessions';
  1083 
  1084 * several improvements in isabelle style files; \isabellestyle{it}
  1085 produces fake math mode output; \isamarkupheader is now \section by
  1086 default; see lib/texinputs/isabelle.sty etc.;
  1087 
  1088 
  1089 *** Isar ***
  1090 
  1091 * Isar/Pure: local results and corresponding term bindings are now
  1092 subject to Hindley-Milner polymorphism (similar to ML); this
  1093 accommodates incremental type-inference very nicely;
  1094 
  1095 * Isar/Pure: new derived language element 'obtain' supports
  1096 generalized existence reasoning;
  1097 
  1098 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1099 support accumulation of results, without applying any rules yet;
  1100 useful to collect intermediate results without explicit name
  1101 references, and for use with transitivity rules with more than 2
  1102 premises;
  1103 
  1104 * Isar/Pure: scalable support for case-analysis type proofs: new
  1105 'case' language element refers to local contexts symbolically, as
  1106 produced by certain proof methods; internally, case names are attached
  1107 to theorems as "tags";
  1108 
  1109 * Isar/Pure: theory command 'hide' removes declarations from
  1110 class/type/const name spaces;
  1111 
  1112 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1113 indicate potential overloading;
  1114 
  1115 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1116 
  1117 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1118 "{a,b,c}" instead of {a,b,c};
  1119 
  1120 * Isar/Pure now provides its own version of intro/elim/dest
  1121 attributes; useful for building new logics, but beware of confusion
  1122 with the version in Provers/classical;
  1123 
  1124 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1125 case name 'antecedent';
  1126 
  1127 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1128 to the current context is now done automatically);
  1129 
  1130 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1131 for definining proof methods in ML;
  1132 
  1133 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1134 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1135 most cases, one should have to change intro!! to intro? only);
  1136 replaced "delrule" by "rule del";
  1137 
  1138 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1139 'symmetric' attribute (the latter supercedes [RS sym]);
  1140 
  1141 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1142 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1143 well (including splits);
  1144 
  1145 * Isar/Provers: Simplifier and Classical methods now support all kind
  1146 of modifiers used in the past, including 'cong', 'iff', etc.
  1147 
  1148 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1149 of Simplifier and Classical reasoner);
  1150 
  1151 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1152 now support named cases; major packages (inductive, datatype, primrec,
  1153 recdef) support case names and properly name parameters;
  1154 
  1155 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1156 monotonicity conditions are extracted to be proven at end of
  1157 calculations;
  1158 
  1159 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1160 method anyway;
  1161 
  1162 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1163 split_if split_if_asm; datatype package provides theorems foo.splits =
  1164 foo.split foo.split_asm for each datatype;
  1165 
  1166 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1167 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1168 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1169 use "(cases (simplified))" method in proper proof texts);
  1170 
  1171 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1172 
  1173 * Isar: names of theorems etc. may be natural numbers as well;
  1174 
  1175 * Isar: 'pr' command: optional arguments for goals_limit and
  1176 ProofContext.prems_limit; no longer prints theory contexts, but only
  1177 proof states;
  1178 
  1179 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1180 additional print modes to be specified; e.g. "pr(latex)" will print
  1181 proof state according to the Isabelle LaTeX style;
  1182 
  1183 * Isar: improved support for emulating tactic scripts, including proof
  1184 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1185 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1186 (for HOL datatypes);
  1187 
  1188 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1189 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1190 'proof method scripts' have to be in depth-first order;
  1191 
  1192 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1193 
  1194 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1195 should instead use individual commands for printing items
  1196 (print_commands, print_methods etc.);
  1197 
  1198 * Isar: added 'nothing' --- the empty list of theorems;
  1199 
  1200 
  1201 *** HOL ***
  1202 
  1203 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1204 corresponding virtual machine and a specification of its bytecode
  1205 verifier and a lightweight bytecode verifier, including proofs of
  1206 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1207 Cornelia Pusch (see also the homepage of project Bali at
  1208 http://isabelle.in.tum.de/Bali/);
  1209 
  1210 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1211 Clemens Ballarin;
  1212 
  1213 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1214 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1215 Rasmussen;
  1216 
  1217 * HOL/Lattice: fundamental concepts of lattice theory and order
  1218 structures, including duals, properties of bounds versus algebraic
  1219 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1220 Theorem for complete lattices etc.; may also serve as a demonstration
  1221 for abstract algebraic reasoning using axiomatic type classes, and
  1222 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1223 
  1224 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1225 von Oheimb;
  1226 
  1227 * HOL/IMPP: extension of IMP with local variables and mutually
  1228 recursive procedures, by David von Oheimb;
  1229 
  1230 * HOL/Lambda: converted into new-style theory and document;
  1231 
  1232 * HOL/ex/Multiquote: example of multiple nested quotations and
  1233 anti-quotations -- basically a generalized version of de-Bruijn
  1234 representation; very useful in avoiding lifting of operations;
  1235 
  1236 * HOL/record: added general record equality rule to simpset; fixed
  1237 select-update simplification procedure to handle extended records as
  1238 well; admit "r" as field name;
  1239 
  1240 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1241 other numeric types and also as the identity of groups, rings, etc.;
  1242 
  1243 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1244 Types nat and int belong to this axclass;
  1245 
  1246 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1247    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1248    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1249   two terms #m*u and #n*u are replaced by #(m+n)*u
  1250     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1251   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1252     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1253 
  1254 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1255 powerful prover for predicate logic but knows nothing of clasets; see
  1256 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1257 
  1258 * HOL: new version of "case_tac" subsumes both boolean case split and
  1259 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1260 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1261 
  1262 * HOL: simplification no longer dives into case-expressions: only the
  1263 selector expression is simplified, but not the remaining arms; to
  1264 enable full simplification of case-expressions for datatype t, you may
  1265 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1266 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1267 
  1268 * HOL/recdef: the recursion equations generated by 'recdef' for
  1269 function 'f' are now called f.simps instead of f.rules; if all
  1270 termination conditions are proved automatically, these simplification
  1271 rules are added to the simpset, as in primrec; rules may be named
  1272 individually as well, resulting in a separate list of theorems for
  1273 each equation;
  1274 
  1275 * HOL/While is a new theory that provides a while-combinator. It
  1276 permits the definition of tail-recursive functions without the
  1277 provision of a termination measure. The latter is necessary once the
  1278 invariant proof rule for while is applied.
  1279 
  1280 * HOL: new (overloaded) notation for the set of elements below/above
  1281 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1282 
  1283 * HOL: theorems impI, allI, ballI bound as "strip";
  1284 
  1285 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1286 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1287 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1288 
  1289 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1290 
  1291 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1292 main HOL, but was unused);
  1293 
  1294 * HOL: fewer consts declared as global (e.g. have to refer to
  1295 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1296 
  1297 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1298 in case of overlap with user translations (e.g. judgements over
  1299 tuples); (note that the underlying logical represenation is still
  1300 bogus);
  1301 
  1302 
  1303 *** ZF ***
  1304 
  1305 * ZF: simplification automatically cancels common terms in arithmetic
  1306 expressions over nat and int;
  1307 
  1308 * ZF: new treatment of nat to minimize type-checking: all operators
  1309 coerce their operands to a natural number using the function natify,
  1310 making the algebraic laws unconditional;
  1311 
  1312 * ZF: as above, for int: operators coerce their operands to an integer
  1313 using the function intify;
  1314 
  1315 * ZF: the integer library now contains many of the usual laws for the
  1316 orderings, including $<=, and monotonicity laws for $+ and $*;
  1317 
  1318 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1319 simplification;
  1320 
  1321 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1322 to the simplifier and classical reasoner simultaneously;
  1323 
  1324 
  1325 *** General ***
  1326 
  1327 * Provers: blast_tac now handles actual object-logic rules as
  1328 assumptions; note that auto_tac uses blast_tac internally as well;
  1329 
  1330 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1331 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1332 
  1333 * Provers: delrules now handles destruct rules as well (no longer need
  1334 explicit make_elim);
  1335 
  1336 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1337   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1338 use instead the strong form,
  1339   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1340 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1341 from destruct-rules;
  1342 
  1343 * Provers: Simplifier.easy_setup provides a fast path to basic
  1344 Simplifier setup for new object-logics;
  1345 
  1346 * Pure: AST translation rules no longer require constant head on LHS;
  1347 
  1348 * Pure: improved name spaces: ambiguous output is qualified; support
  1349 for hiding of names;
  1350 
  1351 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1352 XSYMBOL_HOME; no longer need to do manual configuration in most
  1353 situations;
  1354 
  1355 * system: compression of ML heaps images may now be controlled via -c
  1356 option of isabelle and isatool usedir (currently only observed by
  1357 Poly/ML);
  1358 
  1359 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1360 useful for remote X11);
  1361 
  1362 * system: provide TAGS file for Isabelle sources;
  1363 
  1364 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1365 order;
  1366 
  1367 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1368 timing flag supersedes proof_timing and Toplevel.trace;
  1369 
  1370 * ML: new combinators |>> and |>>> for incremental transformations
  1371 with secondary results (e.g. certain theory extensions):
  1372 
  1373 * ML: PureThy.add_defs gets additional argument to indicate potential
  1374 overloading (usually false);
  1375 
  1376 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1377 results;
  1378 
  1379 
  1380 
  1381 New in Isabelle99 (October 1999)
  1382 --------------------------------
  1383 
  1384 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1385 
  1386 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1387 are no longer simplified.  (This allows the simplifier to unfold recursive
  1388 functional programs.)  To restore the old behaviour, declare
  1389 
  1390     Delcongs [if_weak_cong];
  1391 
  1392 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1393 complement;
  1394 
  1395 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1396 
  1397 * HOL/datatype: mutual_induct_tac no longer exists --
  1398   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1399 
  1400 * HOL/typedef: fixed type inference for representing set; type
  1401 arguments now have to occur explicitly on the rhs as type constraints;
  1402 
  1403 * ZF: The con_defs part of an inductive definition may no longer refer
  1404 to constants declared in the same theory;
  1405 
  1406 * HOL, ZF: the function mk_cases, generated by the inductive
  1407 definition package, has lost an argument.  To simplify its result, it
  1408 uses the default simpset instead of a supplied list of theorems.
  1409 
  1410 * HOL/List: the constructors of type list are now Nil and Cons;
  1411 
  1412 * Simplifier: the type of the infix ML functions
  1413         setSSolver addSSolver setSolver addSolver
  1414 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1415 for packaging solvers. A solver is created via
  1416         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1417 where the string argument is only a comment.
  1418 
  1419 
  1420 *** Proof tools ***
  1421 
  1422 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1423 decision procedure for linear arithmetic. Currently it is used for
  1424 types `nat', `int', and `real' in HOL (see below); it can, should and
  1425 will be instantiated for other types and logics as well.
  1426 
  1427 * The simplifier now accepts rewrite rules with flexible heads, eg
  1428      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1429   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1430   matching.
  1431 
  1432 
  1433 *** General ***
  1434 
  1435 * New Isabelle/Isar subsystem provides an alternative to traditional
  1436 tactical theorem proving; together with the ProofGeneral/isar user
  1437 interface it offers an interactive environment for developing human
  1438 readable proof documents (Isar == Intelligible semi-automated
  1439 reasoning); for further information see isatool doc isar-ref,
  1440 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1441 
  1442 * improved and simplified presentation of theories: better HTML markup
  1443 (including colors), graph views in several sizes; isatool usedir now
  1444 provides a proper interface for user theories (via -P option); actual
  1445 document preparation based on (PDF)LaTeX is available as well (for
  1446 new-style theories only); see isatool doc system for more information;
  1447 
  1448 * native support for Proof General, both for classic Isabelle and
  1449 Isabelle/Isar;
  1450 
  1451 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1452 using the graph browser tool;
  1453 
  1454 * Isabelle manuals now also available as PDF;
  1455 
  1456 * theory loader rewritten from scratch (may not be fully
  1457 bug-compatible); old loadpath variable has been replaced by show_path,
  1458 add_path, del_path, reset_path functions; new operations such as
  1459 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1460 isatool doc ref);
  1461 
  1462 * improved isatool install: option -k creates KDE application icon,
  1463 option -p DIR installs standalone binaries;
  1464 
  1465 * added ML_PLATFORM setting (useful for cross-platform installations);
  1466 more robust handling of platform specific ML images for SML/NJ;
  1467 
  1468 * the settings environment is now statically scoped, i.e. it is never
  1469 created again in sub-processes invoked from isabelle, isatool, or
  1470 Isabelle;
  1471 
  1472 * path element specification '~~' refers to '$ISABELLE_HOME';
  1473 
  1474 * in locales, the "assumes" and "defines" parts may be omitted if
  1475 empty;
  1476 
  1477 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1478 long arrows);
  1479 
  1480 * new print_mode "HTML";
  1481 
  1482 * new flag show_tags controls display of tags of theorems (which are
  1483 basically just comments that may be attached by some tools);
  1484 
  1485 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1486 mode and goal output format:
  1487 
  1488 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1489 244c244
  1490 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1491 ---
  1492 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1493 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1494 181c181
  1495 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1496 ---
  1497 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1498 
  1499 * function bind_thms stores lists of theorems (cf. bind_thm);
  1500 
  1501 * new shorthand tactics ftac, eatac, datac, fatac;
  1502 
  1503 * qed (and friends) now accept "" as result name; in that case the
  1504 theorem is not stored, but proper checks and presentation of the
  1505 result still apply;
  1506 
  1507 * theorem database now also indexes constants "Trueprop", "all",
  1508 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1509 
  1510 
  1511 *** HOL ***
  1512 
  1513 ** HOL arithmetic **
  1514 
  1515 * There are now decision procedures for linear arithmetic over nat and
  1516 int:
  1517 
  1518 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1519 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1520 are treated as atomic; subformulae not involving type `nat' or `int'
  1521 are ignored; quantified subformulae are ignored unless they are
  1522 positive universal or negative existential. The tactic has to be
  1523 invoked by hand and can be a little bit slow. In particular, the
  1524 running time is exponential in the number of occurrences of `min' and
  1525 `max', and `-' on `nat'.
  1526 
  1527 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1528 (negated) (in)equalities among the premises and the conclusion into
  1529 account (i.e. no compound formulae) and does not know about `min' and
  1530 `max', and `-' on `nat'. It is fast and is used automatically by the
  1531 simplifier.
  1532 
  1533 NB: At the moment, these decision procedures do not cope with mixed
  1534 nat/int formulae where the two parts interact, such as `m < n ==>
  1535 int(m) < int(n)'.
  1536 
  1537 * HOL/Numeral provides a generic theory of numerals (encoded
  1538 efficiently as bit strings); setup for types nat/int/real is in place;
  1539 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1540 int, existing theories and proof scripts may require a few additional
  1541 type constraints;
  1542 
  1543 * integer division and remainder can now be performed on constant
  1544 arguments;
  1545 
  1546 * many properties of integer multiplication, division and remainder
  1547 are now available;
  1548 
  1549 * An interface to the Stanford Validity Checker (SVC) is available through the
  1550 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1551 are proved automatically.  SVC must be installed separately, and its results
  1552 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1553 invocation of the underlying oracle).  For SVC see
  1554   http://verify.stanford.edu/SVC
  1555 
  1556 * IsaMakefile: the HOL-Real target now builds an actual image;
  1557 
  1558 
  1559 ** HOL misc **
  1560 
  1561 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1562 (in Isabelle/Isar) -- by Gertrud Bauer;
  1563 
  1564 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1565 analysis for assembly languages with subtypes;
  1566 
  1567 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1568 -- avoids syntactic ambiguities and treats state, transition, and
  1569 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1570 changed syntax and (many) tactics;
  1571 
  1572 * HOL/inductive: Now also handles more general introduction rules such
  1573   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1574   theorems are now maintained within the theory (maintained via the
  1575   "mono" attribute);
  1576 
  1577 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1578   (using function types) such as
  1579 
  1580   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1581 
  1582 * HOL/record: record_simproc (part of the default simpset) takes care
  1583 of selectors applied to updated records; record_split_tac is no longer
  1584 part of the default claset; update_defs may now be removed from the
  1585 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1586 
  1587   claset_ref () := claset() addSWrapper record_split_wrapper;
  1588   Delsimprocs [record_simproc]
  1589 
  1590 * HOL/typedef: fixed type inference for representing set; type
  1591 arguments now have to occur explicitly on the rhs as type constraints;
  1592 
  1593 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1594 names rather than an ML expression;
  1595 
  1596 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1597 supplied later.  Program schemes can be defined, such as
  1598     "While B C s = (if B s then While B C (C s) else s)"
  1599 where the well-founded relation can be chosen after B and C have been given.
  1600 
  1601 * HOL/List: the constructors of type list are now Nil and Cons;
  1602 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1603 course, ML tools referring to List.list.op # etc. have to be adapted;
  1604 
  1605 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1606 disabled by default; run isabelle with option -m HOL to get back to
  1607 the original Gordon/HOL-style output;
  1608 
  1609 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1610 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1611 
  1612 * HOL basic syntax simplified (more orthogonal): all variants of
  1613 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1614 Eps operator is provided as well: "SOME x. P[x]";
  1615 
  1616 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1617 
  1618 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1619 thus available for user theories;
  1620 
  1621 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1622 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1623 time;
  1624 
  1625 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1626 several times and then mp;
  1627 
  1628 
  1629 *** LK ***
  1630 
  1631 * the notation <<...>> is now available as a notation for sequences of
  1632 formulas;
  1633 
  1634 * the simplifier is now installed
  1635 
  1636 * the axiom system has been generalized (thanks to Soren Heilmann)
  1637 
  1638 * the classical reasoner now has a default rule database
  1639 
  1640 
  1641 *** ZF ***
  1642 
  1643 * new primrec section allows primitive recursive functions to be given
  1644 directly (as in HOL) over datatypes and the natural numbers;
  1645 
  1646 * new tactics induct_tac and exhaust_tac for induction (or case
  1647 analysis) over datatypes and the natural numbers;
  1648 
  1649 * the datatype declaration of type T now defines the recursor T_rec;
  1650 
  1651 * simplification automatically does freeness reasoning for datatype
  1652 constructors;
  1653 
  1654 * automatic type-inference, with AddTCs command to insert new
  1655 type-checking rules;
  1656 
  1657 * datatype introduction rules are now added as Safe Introduction rules
  1658 to the claset;
  1659 
  1660 * the syntax "if P then x else y" is now available in addition to
  1661 if(P,x,y);
  1662 
  1663 
  1664 *** Internal programming interfaces ***
  1665 
  1666 * tuned simplifier trace output; new flag debug_simp;
  1667 
  1668 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1669 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1670 
  1671 * AxClass.axclass_tac lost the theory argument;
  1672 
  1673 * tuned current_goals_markers semantics: begin / end goal avoids
  1674 printing empty lines;
  1675 
  1676 * removed prs and prs_fn hook, which was broken because it did not
  1677 include \n in its semantics, forcing writeln to add one
  1678 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1679 string -> unit if you really want to output text without newline;
  1680 
  1681 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1682 plain output, interface builders may have to enable 'isabelle_font'
  1683 mode to get Isabelle font glyphs as before;
  1684 
  1685 * refined token_translation interface; INCOMPATIBILITY: output length
  1686 now of type real instead of int;
  1687 
  1688 * theory loader actions may be traced via new ThyInfo.add_hook
  1689 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1690 your own database of information attached to *whole* theories -- as
  1691 opposed to intra-theory data slots offered via TheoryDataFun;
  1692 
  1693 * proper handling of dangling sort hypotheses (at last!);
  1694 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1695 extra sort hypotheses that can be witnessed from the type signature;
  1696 the force_strip_shyps flag is gone, any remaining shyps are simply
  1697 left in the theorem (with a warning issued by strip_shyps_warning);
  1698 
  1699 
  1700 
  1701 New in Isabelle98-1 (October 1998)
  1702 ----------------------------------
  1703 
  1704 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1705 
  1706 * several changes of automated proof tools;
  1707 
  1708 * HOL: major changes to the inductive and datatype packages, including
  1709 some minor incompatibilities of theory syntax;
  1710 
  1711 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1712 called `inj_on';
  1713 
  1714 * HOL: removed duplicate thms in Arith:
  1715   less_imp_add_less  should be replaced by  trans_less_add1
  1716   le_imp_add_le      should be replaced by  trans_le_add1
  1717 
  1718 * HOL: unary minus is now overloaded (new type constraints may be
  1719 required);
  1720 
  1721 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1722 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1723 now taken as an integer constant.
  1724 
  1725 * Pure: ML function 'theory_of' renamed to 'theory';
  1726 
  1727 
  1728 *** Proof tools ***
  1729 
  1730 * Simplifier:
  1731   1. Asm_full_simp_tac is now more aggressive.
  1732      1. It will sometimes reorient premises if that increases their power to
  1733         simplify.
  1734      2. It does no longer proceed strictly from left to right but may also
  1735         rotate premises to achieve further simplification.
  1736      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1737      old Asm_full_simp_tac in that it does not rotate premises.
  1738   2. The simplifier now knows a little bit about nat-arithmetic.
  1739 
  1740 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1741 allows for selected deletion of wrappers, by introduction of names for
  1742 wrapper functionals.  This implies that addbefore, addSbefore,
  1743 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1744 and that adding two tactics with the same name overwrites the first
  1745 one (emitting a warning).
  1746   type wrapper = (int -> tactic) -> (int -> tactic)
  1747   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1748   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1749   delWrapper, delSWrapper: claset *  string            -> claset
  1750   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1751 
  1752 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1753 semantics; addbefore now affects only the unsafe part of step_tac
  1754 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1755 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1756 by Force_tac;
  1757 
  1758 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1759 compWrapper; added safe wrapper (and access functions for it);
  1760 
  1761 * HOL/split_all_tac is now much faster and fails if there is nothing
  1762 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1763 and the names of the automatically generated variables have changed.
  1764 split_all_tac has moved within claset() from unsafe wrappers to safe
  1765 wrappers, which means that !!-bound variables are split much more
  1766 aggressively, and safe_tac and clarify_tac now split such variables.
  1767 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1768 Note: the same holds for record_split_tac, which does the job of
  1769 split_all_tac for record fields.
  1770 
  1771 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1772 permanently to the default simpset using Addsplits just like
  1773 Addsimps. They can be removed via Delsplits just like
  1774 Delsimps. Lower-case versions are also available.
  1775 
  1776 * HOL/Simplifier: The rule split_if is now part of the default
  1777 simpset. This means that the simplifier will eliminate all occurrences
  1778 of if-then-else in the conclusion of a goal. To prevent this, you can
  1779 either remove split_if completely from the default simpset by
  1780 `Delsplits [split_if]' or remove it in a specific call of the
  1781 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1782 other case splitting rules to/from the default simpset: every datatype
  1783 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1784 t is the name of the datatype).
  1785 
  1786 * Classical reasoner / Simplifier combination: new force_tac (and
  1787 derivatives Force_tac, force) combines rewriting and classical
  1788 reasoning (and whatever other tools) similarly to auto_tac, but is
  1789 aimed to solve the given subgoal completely.
  1790 
  1791 
  1792 *** General ***
  1793 
  1794 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1795 and `goalw': the theory is no longer needed as an explicit argument -
  1796 the current theory context is used; assumptions are no longer returned
  1797 at the ML-level unless one of them starts with ==> or !!; it is
  1798 recommended to convert to these new commands using isatool fixgoal
  1799 (backup your sources first!);
  1800 
  1801 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1802 the current theory context, and 'theory' to lookup stored theories;
  1803 
  1804 * new theory section 'locale' for declaring constants, assumptions and
  1805 definitions that have local scope;
  1806 
  1807 * new theory section 'nonterminals' for purely syntactic types;
  1808 
  1809 * new theory section 'setup' for generic ML setup functions
  1810 (e.g. package initialization);
  1811 
  1812 * the distribution now includes Isabelle icons: see
  1813 lib/logo/isabelle-{small,tiny}.xpm;
  1814 
  1815 * isatool install - install binaries with absolute references to
  1816 ISABELLE_HOME/bin;
  1817 
  1818 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1819 
  1820 * print mode 'emacs' reserved for Isamode;
  1821 
  1822 * support multiple print (ast) translations per constant name;
  1823 
  1824 * theorems involving oracles are now printed with a suffixed [!];
  1825 
  1826 
  1827 *** HOL ***
  1828 
  1829 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1830 
  1831 * HOL/inductive package reorganized and improved: now supports mutual
  1832 definitions such as
  1833 
  1834   inductive EVEN ODD
  1835     intrs
  1836       null "0 : EVEN"
  1837       oddI "n : EVEN ==> Suc n : ODD"
  1838       evenI "n : ODD ==> Suc n : EVEN"
  1839 
  1840 new theorem list "elims" contains an elimination rule for each of the
  1841 recursive sets; inductive definitions now handle disjunctive premises
  1842 correctly (also ZF);
  1843 
  1844 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1845 "mutual_induct" no longer exists - the induction rule is always
  1846 contained in "induct";
  1847 
  1848 
  1849 * HOL/datatype package re-implemented and greatly improved: now
  1850 supports mutually recursive datatypes such as
  1851 
  1852   datatype
  1853     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1854             | SUM ('a aexp) ('a aexp)
  1855             | DIFF ('a aexp) ('a aexp)
  1856             | NUM 'a
  1857   and
  1858     'a bexp = LESS ('a aexp) ('a aexp)
  1859             | AND ('a bexp) ('a bexp)
  1860             | OR ('a bexp) ('a bexp)
  1861 
  1862 as well as indirectly recursive datatypes such as
  1863 
  1864   datatype
  1865     ('a, 'b) term = Var 'a
  1866                   | App 'b ((('a, 'b) term) list)
  1867 
  1868 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1869 induction on mutually / indirectly recursive datatypes.
  1870 
  1871 Primrec equations are now stored in theory and can be accessed via
  1872 <function_name>.simps.
  1873 
  1874 INCOMPATIBILITIES:
  1875 
  1876   - Theories using datatypes must now have theory Datatype as an
  1877     ancestor.
  1878   - The specific <typename>.induct_tac no longer exists - use the
  1879     generic induct_tac instead.
  1880   - natE has been renamed to nat.exhaust - use exhaust_tac
  1881     instead of res_inst_tac ... natE. Note that the variable
  1882     names in nat.exhaust differ from the names in natE, this
  1883     may cause some "fragile" proofs to fail.
  1884   - The theorems split_<typename>_case and split_<typename>_case_asm
  1885     have been renamed to <typename>.split and <typename>.split_asm.
  1886   - Since default sorts of type variables are now handled correctly,
  1887     some datatype definitions may have to be annotated with explicit
  1888     sort constraints.
  1889   - Primrec definitions no longer require function name and type
  1890     of recursive argument.
  1891 
  1892 Consider using isatool fixdatatype to adapt your theories and proof
  1893 scripts to the new package (backup your sources first!).
  1894 
  1895 
  1896 * HOL/record package: considerably improved implementation; now
  1897 includes concrete syntax for record types, terms, updates; theorems
  1898 for surjective pairing and splitting !!-bound record variables; proof
  1899 support is as follows:
  1900 
  1901   1) standard conversions (selectors or updates applied to record
  1902 constructor terms) are part of the standard simpset;
  1903 
  1904   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1905 made part of standard simpset and claset via addIffs;
  1906 
  1907   3) a tactic for record field splitting (record_split_tac) is part of
  1908 the standard claset (addSWrapper);
  1909 
  1910 To get a better idea about these rules you may retrieve them via
  1911 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1912 the name of your record type.
  1913 
  1914 The split tactic 3) conceptually simplifies by the following rule:
  1915 
  1916   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1917 
  1918 Thus any record variable that is bound by meta-all will automatically
  1919 blow up into some record constructor term, consequently the
  1920 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1921 solve record problems automatically.
  1922 
  1923 
  1924 * reorganized the main HOL image: HOL/Integ and String loaded by
  1925 default; theory Main includes everything;
  1926 
  1927 * automatic simplification of integer sums and comparisons, using cancellation;
  1928 
  1929 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1930 
  1931 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1932 
  1933 * many new identities for unions, intersections, set difference, etc.;
  1934 
  1935 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1936 called split_if, split_split, split_sum_case and split_nat_case (to go
  1937 with add/delsplits);
  1938 
  1939 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1940 (?x::unit) = (); this is made part of the default simpset, which COULD
  1941 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1942 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1943 unit_abs_eta_conv is added in order to counter the effect of
  1944 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1945 %u.f();
  1946 
  1947 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1948 makes more sense);
  1949 
  1950 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1951   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1952   disjointness reasoning but breaking a few old proofs.
  1953 
  1954 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1955 to 'converse' from 'inverse' (for compatibility with ZF and some
  1956 literature);
  1957 
  1958 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1959 the well-founded relation;
  1960 
  1961 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1962     Compl A.  The "Compl" syntax remains available as input syntax for this
  1963     release ONLY.
  1964 
  1965 * HOL/Update: new theory of function updates:
  1966     f(a:=b) == %x. if x=a then b else f x
  1967 may also be iterated as in f(a:=b,c:=d,...);
  1968 
  1969 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1970 
  1971 * HOL/List:
  1972   - new function list_update written xs[i:=v] that updates the i-th
  1973     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1974   - new function `upt' written [i..j(] which generates the list
  1975     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1976     bound write [i..j], which is a shorthand for [i..j+1(].
  1977   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1978 
  1979 * HOL/Arith:
  1980   - removed 'pred' (predecessor) function;
  1981   - generalized some theorems about n-1;
  1982   - many new laws about "div" and "mod";
  1983   - new laws about greatest common divisors (see theory ex/Primes);
  1984 
  1985 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1986 instead of "inverse";
  1987 
  1988 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1989   of the multiset ordering;
  1990 
  1991 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1992   (not included by default);
  1993 
  1994 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1995 
  1996 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1997   programs, i.e. different program variables may have different types.
  1998 
  1999 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2000   [previously, this check worked only if the rewrite rule was unconditional]
  2001   Now rew can involve either definitions or equalities (either == or =).
  2002 
  2003 
  2004 *** ZF ***
  2005 
  2006 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2007   only the theorems proved on ZF.ML;
  2008 
  2009 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2010   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2011   disjointness reasoning but breaking a few old proofs.
  2012 
  2013 * ZF/Update: new theory of function updates
  2014     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2015   may also be iterated as in f(a:=b,c:=d,...);
  2016 
  2017 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2018 
  2019 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2020   [previously, this check worked only if the rewrite rule was unconditional]
  2021   Now rew can involve either definitions or equalities (either == or =).
  2022 
  2023 * case_tac provided for compatibility with HOL
  2024     (like the old excluded_middle_tac, but with subgoals swapped)
  2025 
  2026 
  2027 *** Internal programming interfaces ***
  2028 
  2029 * Pure: several new basic modules made available for general use, see
  2030 also src/Pure/README;
  2031 
  2032 * improved the theory data mechanism to support encapsulation (data
  2033 kind name replaced by private Object.kind, acting as authorization
  2034 key); new type-safe user interface via functor TheoryDataFun; generic
  2035 print_data function becomes basically useless;
  2036 
  2037 * removed global_names compatibility flag -- all theory declarations
  2038 are qualified by default;
  2039 
  2040 * module Pure/Syntax now offers quote / antiquote translation
  2041 functions (useful for Hoare logic etc. with implicit dependencies);
  2042 see HOL/ex/Antiquote for an example use;
  2043 
  2044 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2045 cterm -> thm;
  2046 
  2047 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2048 subgoal;
  2049 
  2050 * Display.print_goals function moved to Locale.print_goals;
  2051 
  2052 * standard print function for goals supports current_goals_markers
  2053 variable for marking begin of proof, end of proof, start of goal; the
  2054 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2055 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2056 for example;
  2057 
  2058 
  2059 
  2060 New in Isabelle98 (January 1998)
  2061 --------------------------------
  2062 
  2063 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2064 
  2065 * changed lexical syntax of terms / types: dots made part of long
  2066 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2067 
  2068 * simpset (and claset) reference variable replaced by functions
  2069 simpset / simpset_ref;
  2070 
  2071 * no longer supports theory aliases (via merge) and non-trivial
  2072 implicit merge of thms' signatures;
  2073 
  2074 * most internal names of constants changed due to qualified names;
  2075 
  2076 * changed Pure/Sequence interface (see Pure/seq.ML);
  2077 
  2078 
  2079 *** General Changes ***
  2080 
  2081 * hierachically structured name spaces (for consts, types, axms, thms
  2082 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2083 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2084 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2085 long_names for fully qualified output names; NOTE: ML programs
  2086 (special tactics, packages etc.) referring to internal names may have
  2087 to be adapted to cope with fully qualified names; in case of severe
  2088 backward campatibility problems try setting 'global_names' at compile
  2089 time to have enrything declared within a flat name space; one may also
  2090 fine tune name declarations in theories via the 'global' and 'local'
  2091 section;
  2092 
  2093 * reimplemented the implicit simpset and claset using the new anytype
  2094 data filed in signatures; references simpset:simpset ref etc. are
  2095 replaced by functions simpset:unit->simpset and
  2096 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2097 to patch your ML files accordingly;
  2098 
  2099 * HTML output now includes theory graph data for display with Java
  2100 applet or isatool browser; data generated automatically via isatool
  2101 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2102 
  2103 * defs may now be conditional; improved rewrite_goals_tac to handle
  2104 conditional equations;
  2105 
  2106 * defs now admits additional type arguments, using TYPE('a) syntax;
  2107 
  2108 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2109 creates a new theory node; implicit merge of thms' signatures is
  2110 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2111 transfer:theory->thm->thm in (rare) cases;
  2112 
  2113 * improved handling of draft signatures / theories; draft thms (and
  2114 ctyps, cterms) are automatically promoted to real ones;
  2115 
  2116 * slightly changed interfaces for oracles: admit many per theory, named
  2117 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2118 
  2119 * print_goals: optional output of const types (set show_consts and
  2120 show_types);
  2121 
  2122 * improved output of warnings (###) and errors (***);
  2123 
  2124 * subgoal_tac displays a warning if the new subgoal has type variables;
  2125 
  2126 * removed old README and Makefiles;
  2127 
  2128 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2129 
  2130 * removed obsolete init_pps and init_database;
  2131 
  2132 * deleted the obsolete tactical STATE, which was declared by
  2133     fun STATE tacfun st = tacfun st st;
  2134 
  2135 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2136 (which abbreviates $HOME);
  2137 
  2138 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2139 use isatool fixseq to adapt your ML programs (this works for fully
  2140 qualified references to the Sequence structure only!);
  2141 
  2142 * use_thy no longer requires writable current directory; it always
  2143 reloads .ML *and* .thy file, if either one is out of date;
  2144 
  2145 
  2146 *** Classical Reasoner ***
  2147 
  2148 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2149 tactics that use classical reasoning to simplify a subgoal without
  2150 splitting it into several subgoals;
  2151 
  2152 * Safe_tac: like safe_tac but uses the default claset;
  2153 
  2154 
  2155 *** Simplifier ***
  2156 
  2157 * added simplification meta rules:
  2158     (asm_)(full_)simplify: simpset -> thm -> thm;
  2159 
  2160 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2161 logics (again);
  2162 
  2163 * added prems argument to simplification procedures;
  2164 
  2165 * HOL, FOL, ZF: added infix function `addsplits':
  2166   instead of `<simpset> setloop (split_tac <thms>)'
  2167   you can simply write `<simpset> addsplits <thms>'
  2168 
  2169 
  2170 *** Syntax ***
  2171 
  2172 * TYPE('a) syntax for type reflection terms;
  2173 
  2174 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2175 
  2176 * pretty printer: changed order of mixfix annotation preference (again!);
  2177 
  2178 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2179 
  2180 
  2181 *** HOL ***
  2182 
  2183 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2184   with `addloop' of the simplifier to faciliate case splitting in premises.
  2185 
  2186 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2187 
  2188 * HOL/Auth: new protocol proofs including some for the Internet
  2189   protocol TLS;
  2190 
  2191 * HOL/Map: new theory of `maps' a la VDM;
  2192 
  2193 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2194 cancelling out common nat summands from =, <, <= (in)equalities, or
  2195 differences; simplification procedures nat_cancel_factor for
  2196 cancelling common factor from =, <, <= (in)equalities over natural
  2197 sums; nat_cancel contains both kinds of procedures, it is installed by
  2198 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2199 
  2200 * HOL/simplifier: terms of the form
  2201   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2202   are rewritten to
  2203   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2204   and those of the form
  2205   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2206   are rewritten to
  2207   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2208 
  2209 * HOL/datatype
  2210   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2211 
  2212   P(t_case f1 ... fn x) =
  2213      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2214         ...
  2215        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2216      )
  2217 
  2218   and a theorem `split_t_case_asm' of the form
  2219 
  2220   P(t_case f1 ... fn x) =
  2221     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2222         ...
  2223        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2224      )
  2225   which can be added to a simpset via `addsplits'. The existing theorems
  2226   expand_list_case and expand_option_case have been renamed to
  2227   split_list_case and split_option_case.
  2228 
  2229 * HOL/Arithmetic:
  2230   - `pred n' is automatically converted to `n-1'.
  2231     Users are strongly encouraged not to use `pred' any longer,
  2232     because it will disappear altogether at some point.
  2233   - Users are strongly encouraged to write "0 < n" rather than
  2234     "n ~= 0". Theorems and proof tools have been modified towards this
  2235     `standard'.
  2236 
  2237 * HOL/Lists:
  2238   the function "set_of_list" has been renamed "set" (and its theorems too);
  2239   the function "nth" now takes its arguments in the reverse order and
  2240   has acquired the infix notation "!" as in "xs!n".
  2241 
  2242 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2243 
  2244 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2245   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2246 
  2247 * HOL/record: extensible records with schematic structural subtyping
  2248 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2249 still lacks various theorems and concrete record syntax;
  2250 
  2251 
  2252 *** HOLCF ***
  2253 
  2254 * removed "axioms" and "generated by" sections;
  2255 
  2256 * replaced "ops" section by extended "consts" section, which is capable of
  2257   handling the continuous function space "->" directly;
  2258 
  2259 * domain package:
  2260   . proves theorems immediately and stores them in the theory,
  2261   . creates hierachical name space,
  2262   . now uses normal mixfix annotations (instead of cinfix...),
  2263   . minor changes to some names and values (for consistency),
  2264   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2265   . separator between mutual domain defs: changed "," to "and",
  2266   . improved handling of sort constraints;  now they have to
  2267     appear on the left-hand side of the equations only;
  2268 
  2269 * fixed LAM <x,y,zs>.b syntax;
  2270 
  2271 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2272 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2273 
  2274 
  2275 *** FOL and ZF ***
  2276 
  2277 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2278   with `addloop' of the simplifier to faciliate case splitting in premises.
  2279 
  2280 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2281 in HOL, they strip ALL and --> from proved theorems;
  2282 
  2283 
  2284 
  2285 New in Isabelle94-8 (May 1997)
  2286 ------------------------------
  2287 
  2288 *** General Changes ***
  2289 
  2290 * new utilities to build / run / maintain Isabelle etc. (in parts
  2291 still somewhat experimental); old Makefiles etc. still functional;
  2292 
  2293 * new 'Isabelle System Manual';
  2294 
  2295 * INSTALL text, together with ./configure and ./build scripts;
  2296 
  2297 * reimplemented type inference for greater efficiency, better error
  2298 messages and clean internal interface;
  2299 
  2300 * prlim command for dealing with lots of subgoals (an easier way of
  2301 setting goals_limit);
  2302 
  2303 
  2304 *** Syntax ***
  2305 
  2306 * supports alternative (named) syntax tables (parser and pretty
  2307 printer); internal interface is provided by add_modesyntax(_i);
  2308 
  2309 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2310 be used in conjunction with the Isabelle symbol font; uses the
  2311 "symbols" syntax table;
  2312 
  2313 * added token_translation interface (may translate name tokens in
  2314 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2315 the current print_mode); IMPORTANT: user print translation functions
  2316 are responsible for marking newly introduced bounds
  2317 (Syntax.mark_boundT);
  2318 
  2319 * token translations for modes "xterm" and "xterm_color" that display
  2320 names in bold, underline etc. or colors (which requires a color
  2321 version of xterm);
  2322 
  2323 * infixes may now be declared with names independent of their syntax;
  2324 
  2325 * added typed_print_translation (like print_translation, but may
  2326 access type of constant);
  2327 
  2328 
  2329 *** Classical Reasoner ***
  2330 
  2331 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2332 some limitations.  Blast_tac...
  2333   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2334   + ignores elimination rules that don't have the correct format
  2335         (the conclusion MUST be a formula variable)
  2336   + ignores types, which can make HOL proofs fail
  2337   + rules must not require higher-order unification, e.g. apply_type in ZF
  2338     [message "Function Var's argument not a bound variable" relates to this]
  2339   + its proof strategy is more general but can actually be slower
  2340 
  2341 * substitution with equality assumptions no longer permutes other
  2342 assumptions;
  2343 
  2344 * minor changes in semantics of addafter (now called addaltern); renamed
  2345 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2346 (and access functions for it);
  2347 
  2348 * improved combination of classical reasoner and simplifier:
  2349   + functions for handling clasimpsets
  2350   + improvement of addss: now the simplifier is called _after_ the
  2351     safe steps.
  2352   + safe variant of addss called addSss: uses safe simplifications
  2353     _during_ the safe steps. It is more complete as it allows multiple
  2354     instantiations of unknowns (e.g. with slow_tac).
  2355 
  2356 *** Simplifier ***
  2357 
  2358 * added interface for simplification procedures (functions that
  2359 produce *proven* rewrite rules on the fly, depending on current
  2360 redex);
  2361 
  2362 * ordering on terms as parameter (used for ordered rewriting);
  2363 
  2364 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2365 
  2366 * the solver is now split into a safe and an unsafe part.
  2367 This should be invisible for the normal user, except that the
  2368 functions setsolver and addsolver have been renamed to setSolver and
  2369 addSolver; added safe_asm_full_simp_tac;
  2370 
  2371 
  2372 *** HOL ***
  2373 
  2374 * a generic induction tactic `induct_tac' which works for all datatypes and
  2375 also for type `nat';
  2376 
  2377 * a generic case distinction tactic `exhaust_tac' which works for all
  2378 datatypes and also for type `nat';
  2379 
  2380 * each datatype comes with a function `size';
  2381 
  2382 * patterns in case expressions allow tuple patterns as arguments to
  2383 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2384 
  2385 * primrec now also works with type nat;
  2386 
  2387 * recdef: a new declaration form, allows general recursive functions to be
  2388 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2389 
  2390 * the constant for negation has been renamed from "not" to "Not" to
  2391 harmonize with FOL, ZF, LK, etc.;
  2392 
  2393 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2394 infinite lists;
  2395 
  2396 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2397 
  2398 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2399 problems in commutative rings, using axiomatic type classes for + and *;
  2400 
  2401 * more examples in HOL/MiniML and HOL/Auth;
  2402 
  2403 * more default rewrite rules for quantifiers, union/intersection;
  2404 
  2405 * a new constant `arbitrary == @x.False';
  2406 
  2407 * HOLCF/IOA replaces old HOL/IOA;
  2408 
  2409 * HOLCF changes: derived all rules and arities
  2410   + axiomatic type classes instead of classes
  2411   + typedef instead of faking type definitions
  2412   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2413   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2414   + eliminated the types void, one, tr
  2415   + use unit lift and bool lift (with translations) instead of one and tr
  2416   + eliminated blift from Lift3.thy (use Def instead of blift)
  2417   all eliminated rules are derived as theorems --> no visible changes ;
  2418 
  2419 
  2420 *** ZF ***
  2421 
  2422 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2423 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2424 as ZF_cs addSIs [equalityI];
  2425 
  2426 
  2427 
  2428 New in Isabelle94-7 (November 96)
  2429 ---------------------------------
  2430 
  2431 * allowing negative levels (as offsets) in prlev and choplev;
  2432 
  2433 * super-linear speedup for large simplifications;
  2434 
  2435 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2436 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2437 FAIL); can suppress it using the command Delsimps (ex_simps @
  2438 all_simps); De Morgan laws are also now included, by default;
  2439 
  2440 * improved printing of ==>  :  ~:
  2441 
  2442 * new object-logic "Sequents" adds linear logic, while replacing LK
  2443 and Modal (thanks to Sara Kalvala);
  2444 
  2445 * HOL/Auth: correctness proofs for authentication protocols;
  2446 
  2447 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2448 examples on HOL/Auth);
  2449 
  2450 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2451 the rewriter and classical reasoner simultaneously;
  2452 
  2453 * function uresult no longer returns theorems in "standard" format;
  2454 regain previous version by: val uresult = standard o uresult;
  2455 
  2456 
  2457 
  2458 New in Isabelle94-6
  2459 -------------------
  2460 
  2461 * oracles -- these establish an interface between Isabelle and trusted
  2462 external reasoners, which may deliver results as theorems;
  2463 
  2464 * proof objects (in particular record all uses of oracles);
  2465 
  2466 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2467 
  2468 * "constdefs" section in theory files;
  2469 
  2470 * "primrec" section (HOL) no longer requires names;
  2471 
  2472 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2473 
  2474 
  2475 
  2476 New in Isabelle94-5
  2477 -------------------
  2478 
  2479 * reduced space requirements;
  2480 
  2481 * automatic HTML generation from theories;
  2482 
  2483 * theory files no longer require "..." (quotes) around most types;
  2484 
  2485 * new examples, including two proofs of the Church-Rosser theorem;
  2486 
  2487 * non-curried (1994) version of HOL is no longer distributed;
  2488 
  2489 
  2490 
  2491 New in Isabelle94-4
  2492 -------------------
  2493 
  2494 * greatly reduced space requirements;
  2495 
  2496 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2497 
  2498 * searchable theorem database (see the section "Retrieving theorems" on
  2499 page 8 of the Reference Manual);
  2500 
  2501 * new examples, including Grabczewski's monumental case study of the
  2502 Axiom of Choice;
  2503 
  2504 * The previous version of HOL renamed to Old_HOL;
  2505 
  2506 * The new version of HOL (previously called CHOL) uses a curried syntax
  2507 for functions.  Application looks like f a b instead of f(a,b);
  2508 
  2509 * Mutually recursive inductive definitions finally work in HOL;
  2510 
  2511 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2512 translates to the operator "split";
  2513 
  2514 
  2515 
  2516 New in Isabelle94-3
  2517 -------------------
  2518 
  2519 * new infix operator, addss, allowing the classical reasoner to
  2520 perform simplification at each step of its search.  Example:
  2521         fast_tac (cs addss ss)
  2522 
  2523 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2524 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2525 look like (a,b) instead of <a,b>;
  2526 
  2527 * PLEASE NOTE: CHOL will eventually replace HOL!
  2528 
  2529 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2530 It translates to the operator "split".  A new theory of integers is available;
  2531 
  2532 * In ZF, integer numerals now denote two's-complement binary integers.
  2533 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2534 
  2535 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2536 of the Axiom of Choice;
  2537 
  2538 
  2539 
  2540 New in Isabelle94-2
  2541 -------------------
  2542 
  2543 * Significantly faster resolution;
  2544 
  2545 * the different sections in a .thy file can now be mixed and repeated
  2546 freely;
  2547 
  2548 * Database of theorems for FOL, HOL and ZF.  New
  2549 commands including qed, qed_goal and bind_thm store theorems in the database.
  2550 
  2551 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2552 a given theory (thms_of), or find out what theory a theorem was proved in
  2553 (theory_of_thm);
  2554 
  2555 * Bugs fixed in the inductive definition and datatype packages;
  2556 
  2557 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2558 and HOL_dup_cs obsolete;
  2559 
  2560 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2561 have been removed;
  2562 
  2563 * Simpler definition of function space in ZF;
  2564 
  2565 * new results about cardinal and ordinal arithmetic in ZF;
  2566 
  2567 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2568 types;
  2569 
  2570 
  2571 $Id$